/
rack-sparklines.rb
50 lines (45 loc) · 1.58 KB
/
rack-sparklines.rb
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require 'spark_pr'
module Rack
# Render sparkline graphs dynamically from datapoints in a matching CSV file
# (or anything that there is a Handler for).
class Sparklines
DEFAULT_SPARK_OPTIONS = {:has_min => true, :has_max => true, :height => 40, :step => 10}
# Options:
# :spark - Hash of sparkline options. See spark_pr.rb
# :prefix - URL prefix for handled requests. Setting it to "/sparks"
# treats requests like "/sparks/stats.csv" as dynamic sparklines.
# :cacher - Cachers know how to store and stream sparkline PNG data.
# :handler - Handler instances know how to fetch data and pass them
# to the Sparklines library.
def initialize(app, options = {})
@app, @options = app, options
@options[:spark] = DEFAULT_SPARK_OPTIONS.merge(@options[:spark] || {})
end
def call(env)
dup._call(env)
end
def _call(env)
if env['PATH_INFO'][@options[:prefix]] == @options[:prefix]
@data_path = env['PATH_INFO'][@options[:prefix].size+1..-1]
@data_path.sub! /\.png$/, ''
@png_path = @data_path + ".png"
@cacher = @options[:cacher].set(@png_path)
@handler = @options[:handler].set(@data_path)
if !@handler.exists?
return @app.call(env)
end
if !@handler.already_cached?(@cacher)
@handler.fetch do |data|
@cacher.save(data, @options[:spark])
end
end
@cacher.serve(self)
else
@app.call(env)
end
end
def each
@cacher.stream { |part| yield part }
end
end
end